A compact bench-top model of the centrifuge enables continuous cell separation according the density. The apparatus holds a small separation disk equipped with a circular channel (8 ml capacity) interrupted by a septum. A set of isotonic Percoll media with different densities was continuously introduced at one terminal and collected from the other. Under centrifugal force field, cell suspension introduced into the proximal portion of the channel results in continuous separation of cells according to their densities. The performance of the apparatus was demonstrated on separation of human buffy coat containing nucleated cells of more than 100,000,000 among a large population (10,000,000,000) of RBC. The results indicated that the method is capable of separating a large number of nucleated cells with minimum damage for a few hours of operation where neutrophils are well resolved from lymphocytes. The method may be applied to other types of samples including cord blood, blood from small animals, cultured cells, pancreatic ? cell islets, malaria parasites, sperm cells, etc.